Twin Reverb.. last issue.

[Sea Chief]

For all intents and purposes motorboating usually has to do with capacitors not doing their job requiring replacement.
nosaj

Ok I understand this is an avenue to explore. But I do not know which capacitors have relevance: I must narrow down the amp's 30 odd caps to a few surely, or this info cannot really be of any practical help nosaj.

Jon Snell kindly gave me a hint about two, even pointing out which. But the thread has been pulled ( not kind at all mods) so I cannot even refer to this now. All I remember was, on whichever AB 763 schematic he linked me to, the caps were "20-525". That doesn't give me a whole lot to go on to locate these two caps.

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Can anyone help? Another post on that pulled thread, someone even said this "doesn't sound like motorboating" to them. Eh?? So then Im confused what the issue is if something else entirely.

As far as I know if it is "motorboating" ( logic says it hugely likely just has to be).. then it's not uncommon; but that means complexity of alot of www info, & I just don't know where to start.

Thanks, SC

[Sea Chief]

Delta362 Hi there, saw your reply "I had a Twin Reverb in last year with similar helicopter noises. Replacing the tremolo bug solved it." in my emails.

Thanks for this.

Yes I understand this is one common fix: but my rebuild 2 years ago included a new octocoupler, as well as all new doghouse caps.

Therefore I'm inclined to put attempts to fix involving new components last/ IE trying -all- other things beforehand. This just seems logical to me.

Thanks, SC

[Sea Chief]

Anyone know if adding a cap from the 10meg in the trem circuit to ground is an idea?

Ive just seen this done on a 75 super reverb, on a YouTube clip. Fixed it perfectly. The ticking on this one was identical to mine too.

So I can safely say my issue is a "ticking tremolo".. but whether this is also called "motorboating" alas I don't know.

SC

[Sea Chief]

B*llocks to this.. im found my path: im off asking this bird right fkn here! https://www.youtube.com/watch?v=Uk_LsuM8Wq4

[g1]

Make sure you tell her you have logically proven that it can't be a part (all almost new), or workmanship (worked before).

Do you use the trem with speed on 10 a lot? If not, how would you know that the noise absolutely was not there before?
Attached is the standard Fender 'ticking cure' service bulletin. But don't waste your time on it as the noise would have been there before. So it has to be a part issue. Except it can't be a part because they are all basically new. Must be aliens.

[Helmholtz]

Attached is the standard Fender 'ticking cure' service bulletin. .

So a 10nF cap from the neon driver V5b plate to ground.

[Sea Chief]

Make sure you tell her you have logically proven that it can't be a part (all almost new), or workmanship (worked before).

Do you use the trem with speed on 10 a lot? If not, how would you know that the noise absolutely was not there before?
Attached is the standard Fender 'ticking cure' service bulletin. But don't waste your time on it as the noise would have been there before. So it has to be a part issue. Except it can't be a part because they are all basically new. Must be aliens.

I only listen to my new bird now g1. She digs all my xyz logic mumbo jumbo. & doesn't answer back like yous lot :-)

That service doc... really great thanks. I had seen a youtube super reverb clip which added a cap on the 10M, but this confirms it.. so I'll try this & report back.

And lead dress: that is after Ive been reading drifting caps & resistors can affect what flows through the wires, hence understanding now how lead dress can have an effect even if the wires are stiff as can be & couldn't move. So now my brain lets me mince along this new exciting promenade.

I thank you, SC.

[Sea Chief]

So a 10nF cap from the neon driver V5b plate to ground.

Thanks HH. So the10M is v5's "plate resistor"? Anyway let's see what this does.

[g1]

I only listen to my new bird now g1. She digs all my xyz logic mumbo jumbo. & doesn't answer back like yous lot :-)

I could think of a lot worse people to listen to. Knows what she's doing, easy on the ears, and the eyes. Win/win
(make sure you tell her I said that )

[Helmholtz]

Thanks HH. So the10M is v5's "plate resistor"? Anyway let's see what this does.

Yes, you might call the 10M the plate resistor as it connects between the plate and supply voltage (node [A]).

[nosaj]

Am I wrong in the fact that 10M is not the same as 10nF?
nosaj

[Helmholtz]

Am I wrong in the fact that 10M is not the same as 10nF?
nosaj

No.

[nosaj]

Just curious since he's been tossing that number around. Maybe he'll like it.

nosaj

[Sea Chief]

Just curious since he's been tossing that number around. Maybe he'll like it.

nosaj

Im not tossing anything until my new bird authorises it, strictly by hand. I have a 103j / 600v orange drop.. that's the idea isn't it?

[nosaj]

Im not tossing anything until my new bird authorises it, strictly by hand. I have a 103j / 600v orange drop.. that's the idea isn't it?

I guess you'll just have to wait till she answers you.
nosaj